Blood typing in the clinical and transfusion fields is typically currently carried out using agglutination assays either in multi well plates, see for example, U.S. Pat. No. 4,770,856, or in card/column format (e.g. U.S. Pat. No. 5,552,064 and U.S. Pat. No. 5,338,689). Additionally, multiplexed typing can be carried out using flow cytometry, but this requires fluorescent labelling and relatively complex apparatus.
U.S. Pat. No. 4,851,210 describes a blood-typing device based on capillary flow through a membrane, which comprises an array of type-specific antibodies capable of immuno-specifically binding red blood cells. Bound red blood cells may be detected visually by the red colour of the cells, or by using detectable agents such as dyes, detectably labelled antibodies, or detectably labelled affinity ligands.
EP0223978 discloses methods and devices for determining blood group classifications from blood or serum samples, utilising a porous substrate comprising one or more antibodies bound thereto in delimited adsorption areas. Bound red blood cells are detected by a colour signal from erythrocytes bound to the antibodies.
Nevertheless, any current systems which rely on detection by eye generally require a relatively large sample of blood and/or a sufficiently large area for binding the red blood cells, in order that the colour may easily be discernable by eye which it will be appreciated can be undesirable. Moreover, visual detection may not be preferable as this can result in human error and an incorrect interpretation of results. Thus, it may be desirable to utilise an automated system.
It is an object of the present invention to obviate and/or mitigate at least one of the aforementioned disadvantages.